This invention relates to the security field and in particular concerns padlocks used in a variety of settings for maintaining the contents of receptacles in a secure fashion. More particularly, the invention relates to the use of a digital programmable microprocessing interface for the purposes of opening and securing a lock device.
It is commonly known that when an individual is concerned about maintaining articles in a secure environment, people routinely use a variety of locking devices to secure receptacles wherein the material to be safeguarded is retained, such as, for example, safety deposit boxes and lockers. In such settings individuals utilize padlocks of either the key or combination variety on the latches of these containers so as to maintain the contents in a secure fashion. Standard padlocks widely available today consist of three basic types: 1) A standard key lock which operates on the basis of a tumbler system and is actuated by inserting a key into a cylinder at the base of the lock which contains pins or mechanical devices which release a locking bar mechanism when the key is turned. In such padlocks, release of the locking bar mechanism when the key is turned. In such padlocks, release of the locking bar is assisted by a spring; 2) A standard combination padlock which is operated by rotating a numbered dial on the front of such lock body. Attached to the dial internally, is a series of disks which have stops and open gaps cut out such that they are aligned to all be in the same open position by rotation of the dial in both directions based upon a pre-programmed set of numbers derived from a factory which produces the lock. According to this type of lock, once the aforementioned spaces are aligned in the open position, the lock can be opened by pulling down on the lock body; and 3) A standard combination padlock which is operated by turning a series of numbered tumblers to a pre-set combination which aligns gaps in a locking bar to an open position. Once this open position is achieved, the lock is free to disengage when the lock body is pulled away from the locking bar. These types of locks have been available for a considerable period of time. However, unless the user has the key or is able to remember the factory-provided combination, it is not possible to open these locks. Further, it is not possible to change the method by which these locks may be opened. Additionally, it is possible for key tumbler locks to be xe2x80x9cpickedxe2x80x9d open and combination dial locks are susceptible to opening if the tumbler action can be heard, typically with the assistance of an aid for amplifying hearing.
In response to the foregoing and other problems, various electronic locks and lock-boxes incorporating padlocks have been developed. One example of an electronic door lock is xe2x80x9cSelf-Contained Electromechanical Locking Devicexe2x80x9d, U.S. Pat. No. 4,901,545 to Bacon, which teaches an electromechanical lock incorporated into a doorknob for use on an original installation of a door lockset, or for retrofitting onto an existing door lockset. The lock in Bacon is characterized by a doorknob having the usual key-cylinder and tumbler mechanism. Additionally, Bacon comprises a keypad mounted on the top of the doorknob and connected to a computer controller housed within the knob. In turn, the controller is operably connected to a motor also housed within the knob. The motor moves a locking pin, which resides within an aperture adjacent the tumbler mechanism, between a locked and unlocked position. (See Item 65, FIG. 6 and Col. 5, Line 62-Col 6, Line 18). When a correct key-code is entered, the locking pin moves out of engagement with the tumbler mechanism, thereby allowing a key or a turn-key to turn in the key-hole and thus open the lock. Unfortunately, the mechanical linkage of the motor to the tumbler mechanism requires a bulky housing, which is suitable for a door lockset but unsuitable for a padlock, and the small locking pin in Bacon is unsuitable for securing a shackle in a padlock. Further, the lock in Bacon essentially has a two-stage unlocking procedure; first, the key-code must be entered, and second, the key must be turned within the lockset. This two-stage procedure saves battery life by reducing power consumption, but is thus unsuitable for a lock with a one-stage unlocking procedure.
Another example of a lock is found in xe2x80x9cGearshift Lockxe2x80x9d, U.S. Pat. No. 5,561,996 to Chang, which teaches a large padlock that prevents a gearshift from moving out of the park position, thereby preventing theft of the vehicle. The lock in Chang incorporates a lock box having two parallel passages to receive each end of a U-shaped shackle. The shackle has a recess on each end for locking engagement with the box. The lock box incorporates a locking mechanism which engages the recesses when the shackle is inserted within the passages. The locking mechanism embodies a motor having a pinion gear on its output shaft. The top of the pinion gear engages an upper rack gear, while the bottom of the pinion gear engages a lower rack gear. Each rack gear is xe2x80x9cLxe2x80x9d shaped, having a bar mounted perpendicularly on their ends. The rack gears are biased away from each other by a pair of springs, which drive the bars into the recesses. A mechanical key is used to activate a switch to drive the motor in a reverse (unlocking direction) which compresses the springs and urges the rack gears together. The motor is powered by the vehicle battery. It will be apparent to those of skill in the art that the rack gears and springs must be of a sufficient size to resist attempts to break the lock and, accordingly, a relatively large motor and power supply is required to generate sufficient torque to compress the springs and move the rack gears.
When driven in the reverse direction, the upper and lower rack gears are driven inwards, thus disengaging the bars from the recesses, thereby releasing the shackle from the lock box. While the lock in Chang is suitable for a large gearshift lock having an external power source, it is unsuitable for a small padlock requiring a self-contained power supply. Further, the lock in Chang requires the use of a key, and cannot be operated by simply entering a combination or key-code.
xe2x80x9cElectronic Access Card Having Key Pads and Coils and Combination Using the Samexe2x80x9d, U.S. Pat. No. 4,864,115 to Imran and Clark, teaches an electronic access card that can be used to operate real estate agent lock boxes which retain a door key. Such boxes are typically combined with a padlock for securing the box to a doorknob, and are used to give several real estate agents access to a single door key of a dwelling, by affixing the lock box to an outside door of the dwelling. The access card contains a power supply and a plurality of programming features to allow the card to open multiple lock boxes, and to record and limit access time to the lock boxes.
xe2x80x9cElectronic Lock Box, Access Card, System and Methodxe2x80x9d, U.S. Pat. No. 4,851,652 to Imran, teaches a type of real estate agent lock box for retaining a door key combined with a padlock for securing the box to a doorknob. Imran includes an external electronic key, which houses a power supply for operating both the lock box and the padlock. Electromagnetic solenoids are used to move leaf springs to open the lock box and the padlock. It will be apparent to those of skill in the art that springs of sufficient size must be used in order to keep the box secured.
xe2x80x9cImproved Electronic Security Systemxe2x80x9d, WO 93/03246 to Babler, teaches an electronic lock box for storing a mechanical key combined with a padlock for affixing the box to a doorknob. The lock box has a nest on its exterior to receive an electronic key. The lock box further includes an interior computer, an internal locking mechanism for the lock box, and an internal locking mechanism for the padlock. The padlock locking mechanism within the lock box includes a solenoid having a pair of plungers which are spring biased in an outward position to engage the shackle, and can be retracted by an electromagnetic winding within the solenoid to release the shackle.
The external electronic key has a keypad, a computer and a power supply to power both the electronic key and the lock box. To use the electronic key, it is inserted into the nest at which point the computer in the keypad communicates with the keypad in the lock box to establish a combination. At this point the real estate agent can use the keypad to enter a combination to either open the lock box or the shackle. The power to engage and disengage the locking mechanism is provided by batteries located within the external electronic key. While Babler is well suited to the needs of real estate agents, the lock box in Babler is not suitable for use as a simple padlock as the power supply and electronic key are not self-contained within the lock box. Furthermore, the combination of the lock box is not programmable within a self-contained unit.
xe2x80x9cElectronically Controlled Security Container for Retaining Door Keyxe2x80x9d, U.S. Pat. No. 5,791,172 to Deighton, teaches another type of real-estate electronic lock box combined with a padlock. The padlock shackle has a notched arm which engages a fork member pivotally mounted on the container chassis. The fork member is urged by a spring in a direction for disengagement but is retained in engagement by a cam which engages a second tapered wheel connected to the motor gear train. When the motor is driven in a certain direction, the cam is driven along the wheel and finally off the end thereof, permitting the fork to be driven out of engagement with the shackle arm. It will be apparent that the padlock in Deighton is not intended to secure a door shut, but only to retain the lock box on a door handle and, accordingly, in order to adapt Deighton for use as a padlock, a sufficiently large spring biasing device would be necessary to adequately secure the shackle. This is disadvantageous, because a large spring would require a larger motor and self-contained power supply in order to operate the lock. Deighton also incorporates an infrared key and lock actuation system, which is disadvantageous as the key could be lost.
xe2x80x9cElectronic Secure Entry System Apparatus and Methodxe2x80x9d, U.S. Pat. No. 4,609,780 to Clark, teaches another type of real-estate electronic lock box combined with a padlock. A notched shackle having a spring-biased latching member normally engaging the notch can be retracted from the notch with an electromagnetic solenoid, thereby releasing the shackle. A keypad connected to an electronic control board engages the solenoid when the correct keycode is entered into the keypad. However, similar to other prior art, the latching member must be sufficiently sized to prevent the shackle from opening thereby necessitating a larger spring and solenoid, and thus requiring the lock box to be of sufficient size to house the entire mechanism and power supply.
xe2x80x9cElectronic Lockxe2x80x9d, WO 90/15910 to Symons, teaches an electronic lock having a notched shackle engaged by a pair of rods spring-biased outwardly to engage the notches. An electromagnetic solenoid can be activated to retract the rods inwardly, thereby releasing the shackle. Symons has the same disadvantages as other prior art, namely that a spring of sufficient size must be used to ensure the rods securely engage the shackle, thereby necessitating a sufficiently large solenoid and power supply to overcome the force of the springs.
xe2x80x9cLocking Devicesxe2x80x9d, GB 2 144 483 A to Miller et al., teaches two embodiments of an electronic padlock, both of which incorporate a rod which is spring biased to engage a recess in the shackle. Miller incorporates a solenoid or winding to compress the spring and retract the rod from the recess in the shackle. Unfortunately, the use of a spring necessitates a sufficiently sized power supply and solenoid to overcome the force of the spring. Accordingly, the power supply in Miller is external to the padlock, and is incorporated into an external key-device. Further, due to the constraints of batteries, this padlock is not suitable to a key-less, self-contained padlock having a long battery life between battery changes. Finally, the use of solenoids necessitates a shorting bridge to prevent false actuation by a powerful external magnet.
The present invention overcomes the aforementioned deficits in lock technology by providing a lock which incorporates a digital programmable microprocessing interface capable of user-programming and wherein a programmed combination opens the lock. According to one embodiment of a lock of the present invention there can be as many as approximately 10xc3x97106 possible different combinations which may be entered by the user.
According to a further embodiment of a lock of the present invention, operation of the lock is driven by an electric signal derived from a combination which is entered by a user where the electric signal is sent to a motor assembly inside the lock body. A motor assembly of the lock in response to the signal, disengages a set of locking balls from a locking bar or other appropriate device for disengaging a locking mechanism of this invention. With the assistance of a springing mechanism, the locking device opens automatically.
According to a further embodiment of a lock of this invention, there is provided a sensor switch wherein depression of a locking bar to achieve a closed position provides a pulse to a motor assembly which engages a locking mechanism in order to secure the lock in a locked position. At this time, according to this embodiment of the invention, an electronic interface is reset to a ready position and cannot be opened except by reinserting a prearranged code.
According to yet a further embodiment of a lock of this invention, an electric signal of the lock is generated by battery power or other suitable portable energy-providing source.
Further features and advantages of the invention will be apparent from a reading of the detailed description of the invention taken in conjunction with the appended drawings.